Usage
The client has many parameters, which describe what data needs to be downloaded, and how it needs to be converted. There are many ways to use the client, which are described in the following chapters.
Databus Client Parameters
Option | Description | Default |
---|---|---|
-s, --source | Set the source you want to convert. A source can either be a | |
-e, --endpoint | Set the sparql endpoint, where the query should be fired to. If you use a collection you don't need this parameter, because its detected automatically. Otherwise its mandatory. | |
-t, --target | Set the target directory for converted files |
|
-c, --compression | Set the compression format of the output file |
|
-f, --format | Set the file format of the output file |
|
-m, --mapping | Set the mapping file for format-conversion to different format equivalence class | |
-d, --delimiter | Set the delimiter (only necessary for some formats) | , |
-q, --quotation | Set the quotation (only necessary for some formats) | " |
--createMapping | Do you want to create mapping files for mapped sources? | false |
-g, --graphURI | Set the graph uri for mapping from rdf triples to rdf quads | |
-b, --baseURI | set the base URI to resolve relative URIs | |
-o, --overwrite | true -> overwrite files in cache, false -> use cache |
|
--clear | true -> clear Cache |
|
--help | Show this message |
Queries
Various datasets are registered on the DBpedia Databus in the form of files. A query specifies an exact selection of these records of the DBpedia Databus to be processed by the Databus Client. Therefore, the query is one of, if not the most important parameter of the client.
Possible queries
You can pass any query that selects the object of the predicate databus:file
, the name of the variable does not matter. The query should look like.
SELECT ?o WHERE { ?s databus:file ?o}
How to pass queries
There are three different ways to pass a query to the Databus Client:
Pass the query string directly as a parameter.
Note: this option does not work for CLI
Save the query in a file and pass the file path as a parameter.
The file extension of the query file must be
.sparql
or.query
.
Collection URIs are also supported. The client receives the associated query itself.
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